In mathematics, the star product is a method of combining graded posets with unique minimal and maximal elements, preserving the property that the posets are Eulerian.
The star product of two graded posets
has a unique maximal element
has a unique minimal element
on the set
We define the partial order
if and only if: In other words, we pluck out the top of
and the bottom of
are the Boolean algebra on two elements.
is the poset with the Hasse diagram below.
The star product of Eulerian posets is Eulerian.
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